US President Donald Trump called the decision an "unprecedented" move which "recognizes the reality that Iran is not only a State Sponsor of Terrorism, but that the IRGC actively participates in, finances, and promotes terrorism as a tool of statecraft."

"The IRGC is the Iranian government's primary means of directing and implementing its global terrorist campaign," Trump said.

A US move to blacklist the IRGC as a terrorist organization has been rumored for several months. The Islamic Republic has promised a “crushing” response if the United States goes through with the move.

Tensions between the US and Iran are already high following Trump’s withdrawal last May from the nuclear deal between Iran and world powers. Trump later imposed two rounds of sanctions on Iran, the latest of which went into effect in November of 2018.

President Trump has made containment of Iranian aggression a focus of his foreign policy. In May 2018 he withdrew from the 2015 nuclear deal with Iran and has since reimposed sanctions on the Islamic Republic.

Last week, a US official stated that the administration is is considering additional sanctions against Iran that would target areas of its economy that have not been hit before, according to Reuters.

The official said the administration aimed to follow through with new sanctions around the first anniversary of the US withdrawal from the 2015 nuclear deal between Iran and several world powers, which President Donald Trump announced last May.

“We just want a continued chilling effect,” the official was quoted by Reuters as having said. “We want businesses to continue to think doing business with Iran is a terrible idea at this point.

Prime Minister Binyamin Netanyahu thanked President Trump for the decision.

"Thank you, my dear friend, US President Donald Trump, for having decided to declare Iran's Revolutionary Guards a terrorist organization. Thank you for responding to another important request of mine, which serves the interests of our countries and the countries of the region. We will continue to work together in every way against the Iranian regime, which threatens the State of Israel, the US and world peace," Netanyahu said.